Northern Irish paramilitaries and Afghan Sikhs are involved in selling DVDs in the UK, according to the Federation Against Copyright Theft (Fact), the industry's anti-piracy unit.

But Fact director general Raymond Leinster admitted terrorist involvement was not rife in mainland Britain.

"I do accept it's maybe more regionalised and it's not a problem widespread throughout the whole of the United Kingdom," he told BBC News Online.

But the campaign emphasises that other organised criminals including people traffickers, drug dealers and paedophile rings are likely to be involved if terrorists are not.

In London and surrounding counties, Mr Leinster said, the culprits were more likely to be Chinese gangs who forced illegal immigrants to sell DVDs on the streets.

"By purchasing pirated DVDs, many consumers are unwittingly helping to fund hardcore criminals with links to people trafficking, drugs, guns and money laundering," he said.

"The potential high returns and relatively low risks mean that organised crime groups have got into DVD piracy in a big way."

The group behind the campaign, The Industry Trust for Intellectual Property Awareness, includes the UK home entertainment arms of Hollywood studios and retailers such as HMV and Asda.

It says pirate DVD seizures in the first half of 2004 more than tripled compared with the same period in 2003.

But there are still 7,000 markets selling pirate DVDs or videos in the UK every weekend, causing an estimated loss to the film industry of £400m-500m in 2003. It is predicted to rise to £1bn within three years, it says.

As well as the alleged criminal links, film fans are also likely to get a poor viewing experience from the copies, the campaign says.

It says nine out of 10 pirated DVDs of films that have not yet been officially released are filmed from the back of a cinema with a camcorder.

Jonathan Ross said of the pirate DVDs he bought: "Without exception, they were rubbish, they were shaky, out of focus, camerawork was bad, they had muffled sound - they were a cheap, shoddy, second-rate version of the original.

The "romantic, Robin Hood image of DVD pirates" was far from reality, he said, telling film fans they had a choice.

"Either they can buy genuine high-quality DVDs and support all the people that keep the home entertainment industry going in this country.

'Unsavoury individuals'

"Or they can buy the hooky gear and put the money into the pockets of some very unsavoury individuals indeed."

Copies of Spider-Man 2, which has its UK premiere in London on Monday, have already appeared for sale on UK streets and the internet.

That is a fact acknowledged by Marek Antoniak, managing director of Columbia Tristar Home Entertainment, which will eventually release the film's official DVD.